Pneumatic saw



W. ZIELONKA March 19, 1940.

I PNEUMATIC 's'Aw Filed Dec. 21, 1938 2 Sheets-Sheet 2 ILZ///// 7174 Z zfer ATTORNEY Patented Mar. I l 9, 1940 UNITED STATES PATENT oFF c PNEUMATIC SAW Walter Zieionka, Warren, Mass.

Application December 21, 1938, Serial No. 247,128

5 Claims.

My invention relates to saws which are portable or semi-portable and which may be carried from one location to another where they may be readily set up for operation. bination disclosed in my specification discloses a pneumatic motor and a saw operated thereby, it will be understood that any other tool may be just as well actuated by said motor and that no or only a slight modification would be required to effect that purpose.

Having briefly outlined the purpose of my invention, I shall now describe same in detail with reference to the accompanying drawings, which:

Fig. 1 shows a side View of my saw including motor and equipment.

Fig. 2 shows a top view of my saw including motor and equipment.

Fig. 3 shows a sectional View of a detail of. the construction shown in Figs. 3. and 2, taken on line 3..l of Fig. 2.

Fig. 4 shows a vertical sectional view taken through the motor shown in Fig. l on line li of same.

Fig. 5 shows a longitudinal sectional view of the motor.

Fig. 6 shows a longitudinal sectional view of the motor with valves in a different position.

Fig. 7 shows a vertical sectional View taken on line l'l of Fig. 5.

Fig. 8 shows a vertical sectional view taken on line 8-8 of Fig. 5.

Fig. 9 shows a vertical sectional view taken on line 9-9 of Fig. 6, but with piston removed from the motor. 7

- Fig. 10 shows an enlarged view of a ratchet arrangement being a part of the construction disclosed in Fig. 1. Fig. 11 shows a fragmentary View disclosing the connection between a rocker arm and a valve shown in Fig. 5.

Similar numerals refer to throughout the several views. In general, my invention is composed of. a motor iii and a saw it actuated by said motor, it being understood that some other tool may be substituted for the saw. The motor is operated by compressed air which may be delivered from a tank or any other reservoir, indicated by numoral l5, through a flexible hose is through valve it into the interior of the motor. Depending from the lower section of the motor is a pin 2! supporting a beam 25 controlled by cable 2% and serving to hold log 22 in position. No provision for the support of the motor is shown, but as to similar parts While the comrespectively in valve 33.

' on the inside surface of wall it.

this detail no particular construction is claimed and obviously such support may be used as may be best suitable for thepurpose.

After this general description, I shall now describe my invention in detail, starting with the r motor as shown in Fig. 5. The motor comprises a chamber 2% which may be cylindrical in shape, one side of the cylinder being closed by wall 15. The open end of the cylinder is provided with internal threads til, by means of which said chamher it may be screwed upon what will be designated as valve block 38. Said valve block, which may also be cylindrical, is provided with longitudinal passages to accommodate valves 32 and The valves are made in the shape of tubes closed at both sides but are provided with ports or openings. These openings are marked 35, 3'5 and 36 respectively in valve 32, and 3?, 3.6 and Supported on a pin it in chamber 29 is a substantially triangular rocker lit provided at its base with forked arms i2 and d2, which embrace ends of valves 32 and 33 between parallel flanges on said ends, said flanges being marked t4 and ids and Q5 and Mia respectively. A detail showing one of these forked arms is being shown in Fig. 11. The apex of said rocker lii is hingedly attached to a member it remaining under the tension of a coiled spring All, said spring being appropriately seated The purpose of this spring arrangement is to impart to the Secured to the valve block 35 and threaded into it is a hollow cylinder it, closed at the outside end by cap Mi. Disposed within the cylinder is piston 50 adapted for a slidable reciprocal action there- ,in, said piston being mounted on shaft ii.

Mounted within the cylinder on the inside wall of cap ii is another rocker 54 pivotally su 'Jr'ted on brackets 55, the body of said rocker being provided with an opening to accommodate 5i and a rod 552, which extends from the end of valve 32 and passes through cap iii. Numerals- 52 and 53 indicate packing for said shaft for said rod respectively. It must be added that piston iii: is provided with an air-tight aperture hi to provide for sliding passage of valve In order to complete thedescription of the motor it], it will be necessary to point out that valve block 3! is provided with two outlets 58 and 59, these outlets being placed so that they areialternately in registry with ports 35 and '38 on valves 32 and 33 respectively. The outlets 58 and 59 lead to a common port 60 on the side of the block, as shown in Fig. 8.

Before describing other elements of my power saw, I shall now describe the operation of the motor. As stated before, the motor is designed to be operated by compressed air. Said air, conducted from tank 15 through hose l 3 and through inlet l4a, enters chamber 29, as shown in Fig. 5. From the chamber it enters inlet 3'! of the lower valve 33 and is forced out at the other end of the valve through port 39 into the inside of the cylinder 48 into a space between piston 50 and valve block 3|. Here it exerts pressure against piston 5i], pushing said piston to the outer end of the cylinder. Air which is contained in said cylinder on the opposite side of piston 50, that is within the space between piston 50 and cap 49, is forced out from said space through port 36 in valve 32, and passing through the length of said valve comes out through outlet 35 when it is conducted through a conduit 58 in the valve block 3i to port 60. When, however, piston 56 reaches the outer end of cylinder 48, it is forced against lug 54a of the rocker 54, whereupon the opposite arm 54b of said rocker swings inwardly into the cylinder and pushes valve 32 inwardly into the cylinder so that its opposite end, provided with flanges 44 and 44a, is projected into the interior of chamber 29. When this occurs, rocker 40, pivoted on pin 4| and actuated by said valve 32, reverses its position and with the aid of spring 4'! snaps valve 33 inwardly. The new position of the rocker and valves is shown in Fig. 6. It will be seen that in this new position inlet 31 is closed by having been moved into the interior of block 3|.

Compressed air, which continues coming into chamber 29, is now diverted into inlet 34 of valve 32 and is forced out at the other end of the valve through outlet 36. Released into the space between piston 51 and cap 49, it forces the piston inwardly in the direction of the valve block 3|, while air contained on the other side of piston 50 is forced out through port 39 and escapes by means of outlet 59 into the discharge port 60. Piston 5i] continues to move so until it comes in contact with the end of valve 33 protruding into the inside of cylinder 48, whereupon said end is pushed towards the block 3|. As a result thereof, the opposite end of the valve is made to actuate the rocker 40, whereupon same snaps back into position shown in Fig. 5. When this occurs, inlet 31 is uncovered, inlet 34 is closed and the action of the piston by means of the compressed air conducted into cylinder 48, is repeated as stated above.

Sometimes it may be necessary to adjust the position of valve 32, particularly before the motor is started, and this may be done manually by lever 51 pivoted on axle 62 and provided with a handle 63, said lever being suitably supported on the outside surface of cap 49.

It will be seen from the above description that when compressed air is released into chamber 29, said air causes the piston to move back and forth in a reciprocal motion within the cylinder 48. This movement is utilized for the purpose of actuating any tool, and particularly a saw, which by means of a suitable mounting may be attached to shaft 5! of said motor. This is shown in Figs. 1, 2: and 3 wherein II is a saw mounted in a T block [2, provided with a vertical slot I! to accommodate same. The lateral ends of the T head of said blockare provided with horizontally disposed grooves l8. Afiixed to the sides of the motor 10 by screws or bolts 16 are longitudinal plates 11 extending in parallel with the axis of the motor and beyond cap 49. These plates, which may best be made of cast metal, are provided on the inside surfaces thereof with pro jections or rails l9 and it is on these rails that block i2 is adapted to slide back and forth actuated by the reciprocal motion of piston 50 within cylinder 48. A sectional view of the T block and rails l9 projecting from said plates is shown in Fig. 3.

In order that saw I I may be kept in operative contact with the object to be sawed, which in this case is indicated as a log 22, a special provision was made which will be described as follows:

Log 22 is held in position by claws 23 and 24, afiixed to beam 25, said beam being pivotally and removably mounted by means of a yoke 20 on pin 2| supported in a bracket 26. The latter is placed below the valve block of the motor and is integrally connected therewith. Said beam is best made of two parallel planks held together by bolts or screws, as shown in the drawing. One of the above mentioned claws 24 is movable and may be selectively placed by means of a pin to be inserted through transverse apertures 21 and 27a in beam 25. The arrangement further comprises a cable 28, one end of which is wound on a drum 64; the other end of the cable is looped over pulley 65, passes over sheaves 66 and 8! and is attached to member 69.

It is by means of this cable, which gradually is wound up on drum 54 during the operation of the saw, that said saw H is kept in operative contact with log 22. When, however, the saw cuts into the wood, this contact between the saw and the log may become loose. To overcome this loose contact, therefore, my invention comprises an arrangement whereby the cable may be tightened gradually and progressively and this is accomplished by means of the ratchet arrangement shown in Fig. 10. Said ratchet arrangement co1n prises a double armed lever 70, pivoted on axle ll, which also serves as the axle of the drum. Included in the construction is also a ratchet wheel 12 controlled by a driving pawl 13 and a checking pawl T4. The lever E0 is provided with arm [5 extending upward and adapted to be raised by T block ll every time that the saw progresses in the direction of the motor it. When this is done, that is when said block I? raises arm 15, the driving pawl 73 imparts a rotary motion to wheel l2 and to drum 54 and the slack of the cable is i 7 taken up by said drum. It will be seen, therefore, that as the saw cuts deeper into the log, the cable is progressively wound up on the drum and the saw is kept in close contact with the log being out. There is a possibility, however, that sometimes the drum might rotate faster than would be justified by the cutting action of the saw. If such were the case, the work of the saw would he impeded by excessive friction and the saw would bear too heavily against the material to be out. It was for the purpose of obviating this possibility that a coiled spring 08 was employed by me in this construction. It will be seen that this coiled spring 68 is supported by a bracket l6 and that said spring bears against the lower surface of member 69. When owing to the slow action of the saw the cable is tightened more than ordinarily would be desirable, the cable exerts excessive pull upon member 69 and this pull, being greater than the resistance of spring 68, causes said spring to yield, whereupon the whole lever it! is tipped to one side, raising arm 75 so that it cannot be actuated by block ill until the saw had time to bite deeper into log 22. Then, upon slacking of, the cable, the tension or" the spring will allow lever iii to come back to its normal position so that arm '55 might be again actuated by the shoulder i l of the saw.

It will be obvious that some changes in the construction combination of parts shown herein are possible and that such changes may be made without departing from the principal idea disclosed herein. What I, therefore, wish to claim is as follows: I

1. A motor to be operated by compressed air. comprising a cylinder, a piston disposed therein, an air chamber, a valve block between said cylinder and said chamber, tubular valves slidably disposed in said valve block and adapted to conduct compressed air into said cylinder, and responsive to the action of the piston to direct compressed air from said chamber by means of said valves into the cylinder alternately into the space on one side or the other side of piston, to effect a reciprocating movement of piston.

2. A pneumatic motor comprising a cylinder,

an airtight piston therein, a chamber outside said cylinder, tubular slidable valves connecting said air chamber with the cylinder, provided with inlets and outlets, each valve in turn being adapted to conduct air into the cylinder to one side of the piston while the other is adapted to release air from the opposite side of said piston, the functionof saidtubes changing alternately in response to means actuated by the motion of the piston.

3. A motor adapted to be operated by compressed air, comprising a cylinder, a piston slidably disposed therein, an air chamber disposed at one end of said cylinder, slidable tubular valves disposed in a valve block placed between the cylinder and the air chamber, each valve being provided with any inlet to receive air from the air chamber, a port at the opposite end of the valve torelease air into the cylinder, an intermediate port to release air from said cylinder and means operated by a piston to control the movement of the slidable valves to direct compressed air into the cylinder to one side of the piston, while air on the other side of said piston is released through the other valve, the function of the valves being alternated by said means.

i. A motor comprising a closed cylinder, a piston adaptedto move therein, in a reciprocating motion, a chamber at one end of the said cylinder, a valve block between the air chamber of the cylinder, tubular valves slidably disposedin saidvalve block, one of said valves extending through the movable piston substantially to the further end of the cylinder, each valve being provided with an inlet from the air chamber, a port at its other end and an intermediate outlet within the confines of the valve block, rocker means actuated by the action or" the piston to slide the valves alternately into the chamber,, to alternately convey compressed air into the cylinder to one side of the piston, While the air on the other side is released through the other valve through said intermediate outlet therein.

5. A motor comprising a cylinder, a piston adapted to be actuated therein by compressed air, an air chamber at one end of said cylindena tubular valve to convey air from the air chamber into the cylinder to one side of said piston, a valve to convey air from said air chamber to the other side of said piston, rocker means within the air chamber actuated by the action of the piston to alternately admit air into the valve from the air chamber, said valves acting alternately to release spent air from the cylinder.

WALTER ZIELONKA. 

